package com.ledong.se;

public class TestSymbol {
    public static void main(String[] args) {

        String a = "book";
        String b = "book";
        String c = "";
        String d = "";
        
//        if (a == ) {
//            
//        }
        
        System.out.println(c == d); // true
        System.out.println(c != d); // false
        
        System.out.println(d == ""); //true
        System.out.println(d != ""); // false
        
        
        if (a.equals("book") || b.equals("books")) {
            System.out.println("test || ");
        }
        if (!b.equals(a)) {
            System.out.println("!b.equals(a)");
        }
        if (b != a) {
            System.out.println("b != a");
        }
        if (c != "") {
            System.out.println("c != \" \"");
        }
        if (c == "") {
            System.out.println("c == \"\"");
        }
    }
}
